1. Field of the Invention
The invention relates to a color television system, more particularly to an apparatus for showing a digitized NTSC-encoded video signal on an NTSC or
color television screen.
2. Description of the Related Art
NTSC and PAL are two standard color television systems which are widely used in North America and Europe. The main difference between the two television systems are as follows:
a. The color subcarrier frequency for the NTSC system is 3.58 MHz and is 4.43 MHz for the PAL system.
b. The horizontal sync frequency for the NTSC system is 15734 Hz and is 15625 Hz for the PAL system.
c. The vertical sync frequency for the NTSC system is 59.94 Hz and is 50 Hz for the PAL system.
d. The number of lines per picture (frame) for the NTSC system is 525 and is 625 for the PAL system.
When one frame of an NTSC-encoded video signal is viewed on a PAL television screen, a 0.5 microsecond blank is formed in the horizontal direction. Furthermore, there are 100 horizontal scan lines in which no video image is being displayed. The NTSC-encoded video signal thus appears compressed when viewed on the PAL television screen.